Lighting device



A. CLAUDE LIGHTING DEVICE Filed Aug. 26, 1936 INVENTOR An dr'e Clo ude ATTORNEY Patente'ti l lov. 19 1940 "uNi'T osfsfT -T Es jzsz'isez v I men-ruse nnv'rcn I vAndre CIaudQNanterrc, France, assignor tesocit Ancnyme pour les Applications dc lEiec- 4 tricit et des Gal Bares, Etablisscmentrefllaude 1 a PaztbSiivmacci-pcratienotFranee u Application Admit 26, 193 Serial No. 97,980 Y in etat Britain August 29, 1935 t (Claims. 240'1.1)

, It is known to employ combinationsoi lumi-' nous tubes for lighting. One or these combinetions is termed or neontubes andimercu'ry tubes, the walls or which ,.-are oi transparent-glass, the

5 brillianey oithejlatter tubes being several times 1 v. g,gre ater .th'an that or the neon'tube.

"'"pe'ctrun oi the light emitted bythis com-. bination or two tubes consistshentirelyct lines; .and consequently. doesnot'rendenall colors per-g i iectly. For 'thisreason, it'islip'reierable are-,7 place the mercury, tubes by tubes or which the inner wall contains or is coated with fluorescent substances; 'i'ifltlc iif tubes have a much greater iuminousgeificiency than that oithe usual mer- "i curytubesiand the spectrum of the'light emitted by thein--has a continuous background which ap-H preciably'improves the lightresulting from their combination with neon tubes;

of the-cold is only erfectly-em If; tended .to illustrate the invention of the appligo cacious ii, when lookingln the direction-otgthegw two tubes, the mercury fluorescent tube,"-"when.f

it' is a difluse light tube, is placed behind the neon tube which is transparent. In the opposite direction, however, the said fluorescent tube '25 intercepts the light emitted by the neon tube and the light obtained is colored. It is the same it the fluorescent tube is transparent, for example'made oi. glass containing a uranium salt, and

a the neon tube is a diffuse light tube, for example, so one made of opal glass.

The object or the present invention is to provide a source or light employing combinations of fluorescent tubes with other tubes, such that radiations of different colors are mixed sumciently to avoid undesired colored effects.

The invention comprises disposing the tubes of the combination in a common light-dispersing envelope and separating them sufllciently in such a manner as to obtain the desired luminous e1- 40 feet, and to provide means to suppress or to limit relatively to the area of the envelope the zone of color eflect produced thereon by the absorption by the diflused light tube of light rays received by it from the transparent tube, these 5 means being designed to operate without sensibly diminishing the luminous flux traversing the entire envelope. t

One oi these means comprises placing the two tubes in a diflusing envelope of substantially greater diameter than the sum 0! the diameters or the tubes, and for example equal to at least twice the minimum space occupied by the tubes, 7

and spacing the tubes sumciently from the envelope in order to obtain the desired luminous s5 eflect. a

. Another means comprises disposing. in" the "interioror on the exterior oi the'env'elop'e onthe wall nearest the diflused light tube, an opaque reflecting band for preventirigthe exit of the light emitted by the difiuse light tube and send- 5 .ing back the said light to be mixed with that o! the transparent tube. Thesaid' band is arranged to mask the whole or'the greater part oi'the area 01 the envelope 'wall deflnedby, the

il'iteisiltiillij',with v said. wall'oi the shadow cone 1o jthrown bythe diffused light tube impingediiupoti '-by-li'ght' rays rrom the transparent tube. The ,width 0! the said reflecting band may be for example equalj to the diameter of the fluorescent In certain cases, 'the' se ;two mean's'may be 'em- 7 ployedsimultaneously'.

, In the accompanying drawing; which is in-,

cation by way of example: t 20 Figure'l' is a diagrammatic view showing the arrangement or the luminous tubes irra com- 1 mon cylindrical envelope, taken in section-at right angles to the axis or the envelope,

Figure 2 is a view similar to Fig. 1 ct a modi- 25... flcation. Y r

Figure 3 is an elevation, partly in section, of a completeiamp according to the invention, iigure 4- is a section of Fig. 3 taken enJine In Figure 1, l designates the cylindrical en, v velope tor dispersing the light, 2 a luminous tube emitting diflused light, and a a transparent lightemitting tube. It. will be seenthat, owing to 1 the arrangement of tubes 2 and 3 in the enas veiope, the tube 2 will absorb the major part of the light rays issuing from the tube 3, the part a A, B of the envelope emitting almostexcluslvely right from the tube vz. On the cont y the part A. C, B of the wallwill furnish a substan o, .tially uniform light iormed by mixture of the' radiationsemittedby the tubes 2 and 3. It will be seen that ii the diameter of theenvelope is increased, the lengthol! the part 'A, Bintersected on this'wall by the shadow cone thrown by the tube 2, will increase less rapidly than the diameter of the envelope, whereby the relative importance of the radiation from theportion A,

is j

preventing any direct translation of light from the part A, B, and reflecting the light rays which arrive thereon from the tube 2. At the same time, the rays, which arrive from the tube 3 by reflection on the interior wall of the envelope I, will effect mixture of theserays.

In the construction shown in Figs.r3 and 4, I

denotes the cylindrical envelope, 2 the diflused light tube, and 3 the transparent'tube, as before. 4 designates the opaque reflecting band. 5 and 8 are the ends of the tubes 2 and 3 each containing an electrode, said ends being enclosed inan opaque casing I. The other electrodes are ar: ranged symmetrically with respect to the said electrodes 5, 6 in another opaque casing 8.

It has been found that the luminous flux emitted by the group of tubes through the envelope is not very appreciably less than that emitted by a similar group of bare tubes if the envelope is made of a composite glass comprising at least one layer of opal glass, the thickness of which is of the order of several tenths of a millimeter. This layer may be surrounded for example by one or more layers of transparent glass. The envelope or external tube is suspended for example from the ceiling of the room to be illuminated and itmay carry a reflecting band, such as is shown at l in the drawing, on the wall nearest the ceiling, the diffuse light tube, for example the fluorescent tube 2 containing a deposit of fluorescent material. and being placed above the transparent tube 3 which, in the foregoing case, is an ordinaryneon tube.

It is obvious that as many tubes as are desired may be placed in the envelope so as to produce a light of desired power and color.

Furthermore, the supply transformers may be provided with devices for regulating the current to one or the other of the tubes so as to obtain lights of diflerent tonalities.

I claim:

1. An illuminating apparatus utilizing two electric discharge tubes giving light of different c01- ors adapted to furnish in all points of spaceabout the apparatus and near the same a light of substantially uniform tone, comprising in combination a cylindrical envelope, a transparent discharge tube in said envelope, a difl'using discharge tube in said envelope, said diffusing tube being opaque .to rays emanating from the other tube, the two tubes having their axes located in the samediametrical plane of the envelope, and

a band of opaque and reflecting material positioned on the wall of the envelope, said band being of a size at least equal to that defined by the intersection with the wall of the envelope of the cone of shadow cast by the opaque tube when subjected to the luminous rays emitted by the transparent tube, the diameter of the envelope beingsufllciently large in order that the presence of the reflecting band will not appreciably modify the distribution of luminous intensities in the space about the envelope. I g

2. An apparatus according to claim 1, in which the opaque diffusing tube comprisesa tube coated interiorly with fluorescent material.

3. An illuminating apparatus as claimed in claim 1 wherein the cylindrical envelope is diffusing.

, comprises a tube coated interiorly with fluorescent material. ANDRE CLAUDE. 

